Disk drives typically include a stack of spaced apart, concentric disks mounted on a common shaft, and an actuator arm assembly encased within a housing. The actuator arm assembly comprises a plurality of arms extending into spacings between the disks. Mounted on the distal end of each arm is a resilient load beam which in turn carries a miniaturized gimbal assembly. Included in the gimbal assembly is a slider pivotally attached to a flexure. A magnetic transducer, employed to interact with the disks, is affixed to the slider.
During the data seeking mode, the disks spin at a high speed about a common shaft. The actuator arm assembly moves the arms toward selected data tracks of the disk. The aerodynamics of the moving air between the slider and the disk surface provide sufficient buoyancy to suspend the slider above the disk surface. On the other hand, the spring force of the resilient load beam pushes the slider toward the disk surface. As a result, the slider flies over the disk surface at a very small spacing, which is called the flying height of the slider.
A lower flying height provides many advantages. First, occurrence of data error is substantially reduced as data can be more reliably written onto or retrieved from the disks during the write and read modes, respectively. The lower flying height enables the use of narrower data track widths, which in turn allows higher data storage capacity.
However, there are major obstacles associated with reducing the flying height of the slider. To begin with, the topology of the disk surface, though highly polished, is not at all uniform at microscopic scale. Moreover, the disk surfaces are not rotating about the common shaft at a perfectly perpendicular angle. A minute angular deviation would translate into varying disk-to-slider distances while the disk is spinning. For reliable data writing and reading, the slider has to faithfully follow the topology of the spinning disk, without impacting the disk surface. With a low flying height, this may not be an easy task.
A head gimbal assembly is normally employed to perform the aforesaid function of accommodating the disk surface topology. Basically, the gimbal assembly is designed to dynamically adjust the position of the slider to conform to the irregular disk surface while the disk is spinning. To this end, the flexure inside the gimbal assembly must be sufficiently flexible and yet stiff enough to resist physical deformation.
Various shapes and forms of the flexure have been proposed. One of such flexures is disclosed in Japanese Patent No. 2-18770, issued to T. Yumura, on Jan. 23, 1990. In Yumura, the flexure has parallel edges in the longitudinal direction. Near the edge boundaries, there is a pair of rectangular slots located at the distal end portion of the flexure. As arranged, the rolling and pitching actions are mostly confined to the distal end portion because the proximate end portion of the flexure comprises a sizable area of rigid material which is relatively unyielding. Moreover, the lateral stiffness is significantly weakened, as three parallel apertures separating four narrow strips are arranged in a row at the distal end portion.
The technological trend in disk drive manufacturing is toward miniaturization, and high performance with fast data seeking and writing time. As a consequence, sliders are shrunk down in size and the flying heights are made to be lower. To accommodate these stringent requirements, and for a slider to fly proximately close to the disk surface, the magnetic head suspension system must be, inter alia, low in roll and pitch stiffness and high in lateral stiffness.